More NearCast Model Animations

These computer forecasts are
EXPERIMENTAL
and are used by atmospheric scientists
to assess the value of satellite observations in numerical weather prediction.
Although the accuracy of these products is consistently good, forecast errors can
occur due to non-receipt of data, observation errors, and computer problems. The
forecasts are fully automated and are not always closely monitored by CIMSS
scientists. The risk of using the CCDNM to plan weather-sensitive activities falls
on the user. Feedback will help us improve deficiencies in the CCDNM. Please
forward any comments to the CRASmaster using the
contact form.

About these Forecasts

Information from the GOES-13 sounder water vapor channels help to define the
regions most susceptible to convection on that day. This technique initializes a
trajectory model with Rapid Update Cycle (RUC) winds and precipitable water at
different levels as retrieved from the GOES-13 sounder. The retrieval uses the
three water vapor channels: channels 10 (7.4 microns), 11 (7.0 microns), and
12 (6.5 microns). The shorter wavelength energy typically is emitted from higher
in the atmosphere. GOES sounder weighting functions from channel 10 typically peak
around 600 or 700 mb; weighting functions from channel 12 peak closer to 400 mb.
The exact level is, of course, a function of the air mass and the satellite viewing
angle. These three channels can help to define the distribution of water vapor in
the atmosphere at different levels: the output of the retrieval that combines
the brightness temperatures and initial guess soundings is precipitable water (mm)
at different levels. Such a multi-layer description of the atmospheric water vapor
is not possible with the single water vapor channel on the GOES imager; the
multiple channels of the GOES sounder are required.

This model can predict areas of destabilization (convective potential) if "low"
level moisture moves underneath "upper" level drying. The fields are presented as
moisture change with height. If a region shows the moisture change with height
increasing with time, then that region is becoming more convectively unstable.